This invention relates generally to smelting and more particularly to electrowinning tanks.
Electrowinning tanks are used for the extraction of metals from solution by using electrochemical processes. This type of process is commonly used in the extraction of copper onto plates.
In electrowinning tanks there has been a problem of acid and other chemical fumes. Excess fumes create a hazardous environment for the workers. Venting or using plastic balls, plastic pellets or chemical suppressants have not been totally successful.
Another solution to the problem is described in U.S. Pat. No. 5,470,445, entitled "Electrode Cap with Integral Tank Cover for Acid Mist Collection" issued to Murray et al. on Nov. 28, 1995. In the Murray approach, each electrode within the electrowinning process is equipped with a solid skirt-type of material which assists in forming a solid barrier above the slurry within the tank. The mist is collected between the skirt and the upper layer of the slurry. This mist is then drawn off using pumps and filters.
Unfortunately, in the field, the skirts tend to become cracked, broken, or do not seal with their neighbors. A less than adequate seal is provided allowing ambient air to be pulled through instead of the chemically laden mist.
It is clear that there is a need to be able to clean the mist produced from these tanks so that the toxic chemicals do not create environmental problems.